The author JK Rowling has won permission to build two Hogwarts-style tree houses in the garden of her home, despite complaints from neighbours.

Rowling, 46, plans to build the two-storey structures for her children David, nine, and Kenzie, seven, in the grounds of her17th century mansion in an Edinburgh suburb, at an estimated cost of £250,000.

The author of the Harry Potter series was given permission by City of Edinburgh council despite objections from several neighbours who are already upset by other renovations and building work around her home.

Drawings submitted to the council's planners show the tree-houses will be erected on tall stilts beside mature conifers in the garden. They will have tall cedar shingle conical roofs and be connected by long partly-elevated walkways and a rope bridge.

The buildings will feature turreted windows, pennants, a basket and pulley, and an owl perch. David's playhouse will include a long tunnel under a walkway and a fireman's pole; his sister's boasts a trapdoor, rope ladder, a metal slide and spiral staircase down to the garden.

Members of Cramond and Barnton community council had urged the council to reject the proposals because they believed a gap in a line of trees in her garden meant the tree houses would be visible to passers-by.

Dr Patricia Eason, the community council's secretary, said: "Our concern is without this high and substantial screening belt of conifers, the entrance to the conservation area would be marked by this massive and very high tree house development and this would be quite out of character with the area and unacceptable."

Tom Borthwick, a neighbour of Rowling, said he did not object in principle to large structures being built in people's gardens but this case was different. "I do object if such buildings have a visual impact on the surrounding area and properties and conflict with existing planning policies, particularly in a conservation area," he told planners.

Rowling's application was approved without a vote by the council's planning committee because less than six objections were received.

John Bury, the council's head of planning and building standards, said: "The proposals comply with the development plan and will not adversely impact on the character and appearance of the conservation area."